To quote from Sony's official statement to Thinq.co.uk (linked above):

"We are sorry if users of Linux or other operating systems are disappointed by our decision to issue a firmware upgrade which when installed disables this operating system feature.

We have made the decision to protect the integrity of the console and whilst mindful of the impact on Linux or other operating system users we nevertheless felt it would be in the best interests of the majority of users to pursue this course of action.

As you will be aware we have upgraded and enhanced functionality and features of the console by numerous firmware upgrades over time and this is a very rare instance where a feature will be disabled. Further enhancements are in the pipeline.

Users do have the choice whether to install the firmware upgrade and this is clearly explained to them at the time the firmware upgrade is made available for installation. Furthermore our terms and conditions clearly state that we have the right to revise the PS3's settings and features in order to prevent access to unauthorised or pirated content."